In recent years, various drug delivery systems have been developed which provide sustained release therapy via a sub-dermal insert. Systems have been disclosed which also provide drug delivery systems suitable for transdermal drug administration.
U.S. Pat. No. 3,964,106, commonly assigned, discloses a microsealed pharmaceutical delivery device suitable for implantation or trans-dermal use, as well as vaginal or intrauterine use.
It has now been found, that in the case of nitroglycerin as the drug to be delivered, drug transport is greatly enhanced and drug delivery increased if triglycerides of saturated coconut oil acids, i.e. miglyol oil 812, and isopropyl palmitate alone, or in combination with mineral oil are added to compliment the hydrophilic solvent system in the polymer matrix.
U.S. Pat. No. 3,996,934 also discloses a medical bandage comprising a backing member and a facing member having at least one reservoir containing systemically active drug either as a distinct layer or as a plurality of microcapsules distributed throughout a silicone polymer matrix. Example one discloses a nitroglycerin pad.
Great Britain Patent Application No. GB 2,021,950 discloses a nitroglycerin bandage containing from 1-10 parts of nitroglycerin per 100 parts of carrier. Mineral oil and lanolin are taught to enhance the transport and absorption of nitroglycerine when the carrier is selected from the group consisting of polyethylene, polypropylene, polybutylene or polymethylbutylene.
Despite the prior art teachings, the only topical form of nitroglycerin commercially available at the present time remains ointments or creams which cause staining and require relatively frequent applications over a much larger surface areas than is required by the nitroglycerin pad of the present invention.